This invention relates generally to destruction or alteration of oxidizable materials. More particularly, materials are oxidized to residue in a wet environment with the generated heat captured for further useful work, and with products of reactions removed in a manner to minimize environmental effects.
Until relatively recent times in United States history, anyone with burnable waste material was free to destroy such waste by burning it to ash. Generally, little thought was given to the efficiency of the combustion process, to generated smoke, to accumulated ash, or to the capture of generated heat. With an increasing population, and particularly concentrations of population within confined areas, indiscriminate burning of waste material became an increasing nuisance, and in some cases a hazard to public health.
Through the years more and more restrictions have been placed on indiscriminate burning of waste materials. Today in some localities indiscriminate burning is banned entirely and planned burning in incinerators is severely restricted. Thus burnable waste materials that have a negative value in the sense that additional costs are incurred in their destruction, have an even greater negative value when they must be transported substantial distances to an acceptable destruction site. Generally such acceptable destruction sites are in remote locations where the heat generated in the destruction process has little or no commercial value. On the other hand the burnable waste is normally accumulated at a site where heat has value. In recent times, with the increasing costs of energy sources such as petroleum, heat that could be generated from waste material has considerable value, first in the value of heat itself and second in avoiding the costs of transporting waste material to some remote site.
It is evident that in many cases considerable improvement could be made if waste material could be destroyed at the point of accumulation without violating environmental restrictions. Within strict environmental restraints, conventional burning of waste material is generally impractical due to restrictions on smoke and particulate matter that is permissable in the off-gases.
In some cases waste materials may not be burnable in the strictest sense of conducting a fire, but such materials may be subjected to further oxidation to reduce the volume or to convert hazardous materials to inert materials. Again the process of destruction often is in conflict with environmental restraints.
Among the burnable materials examples include carbonaceous materials such as cellulose, wood products, paper, vegetable fiber and the like. Among the oxidizable materials examples include minerals and their compounds such as sodium, magnesium, calcium, potassium, iron and the like. Anyone of ordinary skill in the art will be able to expand the list of examples considerably.
In order to convert the aforementioned types of materials into residue of significantly smaller volumes or to convert such types of materials from obnoxious form to more acceptable form, within the limits of environmental restraints, burning or dry oxidation generally produces unsatisfactory results. Improved methods can be effected by oxidizing such materials in a wet environment. It is an object of the present invention to teach such methods. Other objects, capabilities and advantages of the present invention will become apparent as the description proceeds.